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 ###Instrução: Qual é a mudança nas taxas de reciclagem para plásticos, papel e metais de 2020 para 2021 para o país 'USA'?
 ###Tabelas: 
CREATE TABLE recycling_rates_history (id INT, country VARCHAR(255), year INT, plastics DECIMAL(3,2), paper DECIMAL(3,2), metals DECIMAL(3,2)); INSERT INTO recycling_rates_history (id, country, year, plastics, paper, metals) VALUES (1, 'USA', 2020, 0.30, 0.55, 0.72), (2, 'USA', 2021, 0.33, 0.58, 0.75);
SELECT  (recycling_rates_history.plastics_2021 - recycling_rates_history.plastics_2020) AS plastics_change, (recycling_rates_history.paper_2021 - recycling_rates_history.paper_2020) AS paper_change, (recycling_rates_history.metals_2021 - recycling_rates_history.metals_2020) AS metals_change FROM (SELECT country, plastics AS plastics_2020, paper AS paper_2020, metals AS metals_2020 FROM recycling_rates_history WHERE year = 2020 AND country = 'USA'  UNION ALL SELECT country, plastics AS plastics_2021, paper AS paper_2021, metals AS metals_2021 FROM recycling_rates_history WHERE year = 2021 AND country = 'USA') AS recycling_rates_history;